我正在寻找在方法minimumlistPerValueOld中转换为minimumlistPerValueNew的getOptimizedTreeNodeResample(TreeNodeResample in, List<Integer> listSampleRateFinal)
/*I need to find the list that by adding it to the nested list,
the minimum number of operations required*/
private static TreeNodeResample getOptimizedTreeNodeResample(TreeNodeResample in, List<Integer> listSampleRateFinal) {
TreeNodeResample out = new TreeNodeResample(null);
listSampleRateFinal.forEach(sampleRateFinal -> {
List<List<NodeResample>> nestedListPerValue = getFilteredNestedListsValue(in, sampleRateFinal);
Long lastMinimum = Long.MAX_VALUE;
List<NodeResample> minimumlistPerValue = null;
for (List<NodeResample> listPerValue : nestedListPerValue) {
Long accumulator = addCalc(out.getNestedListsValue(), listPerValue)
.stream()
.map(nodeResample -> (long) nodeResample.getNumResampleOperations())
.mapToLong(Long::longValue).sum();
if (accumulator < lastMinimum) {
lastMinimum = accumulator;
minimumlistPerValue = listPerValue;
}
}
out.addListValue(minimumlistPerValue);
});
return out;
}
我相信我需要映射
listPerValue，因为您可以看到listPerValue是类型List<NodeResample>listPerValue -> {
TreeNodeResample temp = new TreeNodeResample(null);
temp.setNestedListsValue(out.getNestedListsValue());
temp.addListValue(listPerValue);
return temp.getListNodes();// return List<TreeNodeResample> type
}
或映射（到相同的对象类型）
listPerValue -> {
TreeNodeResample temp = new TreeNodeResample(null);
temp.setNestedListsValue(out.getNestedListsValue());
temp.addListValue(listPerValue);
List<NodeResample> childsValues = temp.getListNodes()
.stream()
.map(node -> node.getValue())
.collect(Collectors.toList());
return childsValues;// return List<NodeResample> type
}
完整的
TreeNodeResample类：import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
public class TreeNodeResample {
TreeNodeResample parent;
List<TreeNodeResample> children;
NodeResample value;
public TreeNodeResample(TreeNodeResample parent) {
this.parent = parent;
children = new ArrayList<>();
}
public TreeNodeResample(TreeNodeResample parent, NodeResample value) {
this.parent = parent;
children = new ArrayList<>();
this.value = value;
}
public void addChild(TreeNodeResample node) {
if (node != null && node.getValue() != null) {//REVIEW (node.getValue() != null) is needed?
if (children.stream().noneMatch(child -> Objects.equals(child.getValue(), node.getValue()))) {
children.add(node);
}
}
}
public TreeNodeResample getParent() {
return parent;
}
public void cleanChildren() {
children = new ArrayList<>();
}
public int getChildrenCount() {
return children.size();
}
public TreeNodeResample getChildrenAt(int position) {
if (children.size() > position && position > -1) {
return children.get(position);
}
return null;
}
public List<TreeNodeResample> getChildren() {
return children;
}
public NodeResample getValue() {
return value;
}
public boolean isLeaf() {
return (children.isEmpty());
}
public List<TreeNodeResample> getLeafs() {
return getLeafs(this);
}
public void addListValue(List<NodeResample> listValue) {
addListValue(this, listValue);
}
public TreeNodeResample getNode(NodeResample value) {
return getNode(this, value);
}
public List<NodeResample> getListValues() {
return getListNodes().stream().map(node -> node.getValue()).collect(Collectors.toList());
}
public List<TreeNodeResample> getListNodes() {
List<TreeNodeResample> listNodes = new ArrayList<>();
getListNodes(this, listNodes);
return listNodes;
}
public List<List<NodeResample>> getNestedListsValue() {
return getNestedListsValue(this);
}
public void setNestedListsValue(List<List<NodeResample>> nestedListsValue) {
setNestedListsValue(this, nestedListsValue);
}
public List<List<NodeResample>> getFilteredNestedListsValue(int sampleRateTarget) {
return getFilteredNestedListsValue(this, sampleRateTarget);
}
public TreeNodeResample getOptimizedTreeNodeResample(List<Integer> listSampleRateFinal) {
return getOptimizedTreeNodeResample(this, listSampleRateFinal);
}
public static void addListValue(TreeNodeResample parent, List<NodeResample> listValue) {
if (listValue != null) {
TreeNodeResample node = parent;
for (NodeResample child : listValue) {
node = getNode(node, child);
}
}
}
public static TreeNodeResample getNode(TreeNodeResample parent, NodeResample value) {
if (parent != null) {//REVIEW (value != null) is needed?
TreeNodeResample node = parent.getChildren().stream()
.filter(child -> child != null)
.filter(child -> Objects.equals(child.getValue(), value))
.findAny().orElse(null);
if (node != null) {
return node;
}
node = new TreeNodeResample(parent, value);
parent.addChild(node);
return node;
} else {
return null;
}
}
public static List<TreeNodeResample> getListNodes(TreeNodeResample parent) {
List<TreeNodeResample> listNodes = new ArrayList<>();
getListNodes(parent, listNodes);
return listNodes;
}
public static void getListNodes(TreeNodeResample parent, List<TreeNodeResample> listNodes) {
if (parent != null) {
listNodes.add(parent);
parent.getChildren().forEach(child -> getListNodes(child, listNodes));
}
}
public static List<List<NodeResample>> getNestedListsValue(TreeNodeResample parent) {
List<TreeNodeResample> listLeafs = getLeafs(parent);
List<List<NodeResample>> nestedListsValues = listLeafs.stream()
.map(leaf -> getParentsListValue(leaf))
.peek(listNodeResample -> {
//System.out.println(Arrays.toString(listNodeResample.toArray()) + System.lineSeparator() + System.lineSeparator());
})
.collect(Collectors.toList());
return nestedListsValues;
}
public static void setNestedListsValue(TreeNodeResample parent, List<List<NodeResample>> nestedListsValue) {
parent.cleanChildren();
nestedListsValue.stream()
.forEachOrdered(listValue -> {
addListValue(parent, listValue);
});
}
public static List<NodeResample> getParentsListValue(TreeNodeResample leaf) {
List<NodeResample> listValue = new ArrayList<>();
if (leaf != null) {
listValue.add(leaf.getValue());
TreeNodeResample node = leaf.getParent();
while (node != null && node.getValue() != null) {
listValue.add(0, node.getValue());
node = node.getParent();
}
}
return listValue;
}
public static List<List<NodeResample>> getFilteredNestedListsValue(TreeNodeResample parent, int sampleRateTarget) {
List<TreeNodeResample> listNodes = getListNodes(parent)
.stream()
.filter(treeNodeResample -> treeNodeResample.getValue() != null)
.filter(treeNodeResample -> treeNodeResample.getValue().getSampleRateTarget() == sampleRateTarget)
.collect(Collectors.toList());
List<List<NodeResample>> nestedListsValues = listNodes.stream()
.map(node -> getParentsListValue(node))
.collect(Collectors.toList());
return nestedListsValues;
}
private static TreeNodeResample getOptimizedTreeNodeResample(TreeNodeResample in, List<Integer> listSampleRateFinal) {
TreeNodeResample out = new TreeNodeResample(null);
listSampleRateFinal.forEach(sampleRateFinal -> {
List<List<NodeResample>> nestedListPerValue = getFilteredNestedListsValue(in, sampleRateFinal);
Long lastMinimum = Long.MAX_VALUE;
List<NodeResample> minimumlistPerValue = null;
for (List<NodeResample> listPerValue : nestedListPerValue) {
Long accumulator = addCalc(out.getNestedListsValue(), listPerValue)
.stream()
.map(nodeResample -> (long) nodeResample.getNumResampleOperations())
.mapToLong(Long::longValue).sum();
if (accumulator < lastMinimum) {
lastMinimum = accumulator;
minimumlistPerValue = listPerValue;
}
}
out.addListValue(minimumlistPerValue);
});
return out;
}
private static List<NodeResample> addCalc(List<List<NodeResample>> nestednestedListValue, List<NodeResample> listPerValue) {
TreeNodeResample temp = new TreeNodeResample(null);
temp.setNestedListsValue(nestednestedListValue);
temp.addListValue(listPerValue);
return temp.getListNodes().stream()
.map(node -> node.getValue())
.filter(nodeResample -> nodeResample != null)
.collect(Collectors.toList());
}
public static List<TreeNodeResample> getLeafs(TreeNodeResample parent) {
List<TreeNodeResample> listLeafs = new ArrayList<>();
getLeafs(parent, listLeafs);
return listLeafs;
}
private static void getLeafs(TreeNodeResample parent, List<TreeNodeResample> listLeafs) {
if (parent != null && listLeafs != null) {
if (parent.isLeaf()) {
listLeafs.add(parent);
} else {
parent.getChildren().forEach(child -> getLeafs(child, listLeafs));
}
}
}
@Override
public String toString() {
return "TreeNodeResample{" + "value=" + value + '}';
}
public static void tempPrintNested(List<List<NodeResample>> nestedListNodeResample) {
System.out.println(" List<List<NodeResample>> nestedListNodeResample = Arrays.asList(");
for (int o = 0; o < nestedListNodeResample.size(); o++) {
List<NodeResample> listNodeResample = nestedListNodeResample.get(o);
System.out.println(" Arrays.asList(");
for (int i = 0; i < listNodeResample.size(); i++) {
NodeResample nodeResample = listNodeResample.get(i);
if (nodeResample != null) {
System.out.print(" " + nodeResample.getCreator());
if (i < listNodeResample.size() - 1) {
System.out.println(",");
} else {
System.out.println("\n )");
}
}
}
if (o < nestedListNodeResample.size() - 1) {
System.out.println(" ,");
}
}
System.out.println(" );");
}
}
另一个
NodeResample类public class NodeResample {
private int incrementL;
private int decrementM;
private int sampleRateSource;
private int sampleRateTarget;
private double maxPassFreq;
private Integer filterSize;
private Integer numResampleOperations;
public NodeResample(int incrementL, int decrementM, int sampleRateSource, int sampleRateTarget, double maxPassFreq, Integer filterSize, Integer numResampleOperations) {
this.incrementL = incrementL;
this.decrementM = decrementM;
this.sampleRateSource = sampleRateSource;
this.sampleRateTarget = sampleRateTarget;
this.maxPassFreq = maxPassFreq;
this.filterSize = filterSize;
this.numResampleOperations = numResampleOperations;
}
public int getIncrementL() {
return incrementL;
}
public void setIncrementL(int incrementL) {
this.incrementL = incrementL;
}
public int getDecrementM() {
return decrementM;
}
public void setDecrementM(int decrementM) {
this.decrementM = decrementM;
}
public int getSampleRateSource() {
return sampleRateSource;
}
public void setSampleRateSource(int sampleRateSource) {
this.sampleRateSource = sampleRateSource;
}
public int getSampleRateTarget() {
return sampleRateTarget;
}
public void setSampleRateTarget(int sampleRateTarget) {
this.sampleRateTarget = sampleRateTarget;
}
public double getMaxPassFreq() {
return maxPassFreq;
}
public void setMaxPassFreq(double maxPassFreq) {
this.maxPassFreq = maxPassFreq;
}
public Integer getFilterSize() {
return filterSize;
}
public void setFilterSize(Integer filterSize) {
this.filterSize = filterSize;
}
public Integer getNumResampleOperations() {
return numResampleOperations;
}
public void setNumResampleOperations(Integer numResampleOperations) {
this.numResampleOperations = numResampleOperations;
}
@Override
public String toString() {
return "NodeResample{" + "L=" + incrementL + ", M=" + decrementM
+ ", Source=" + sampleRateSource + ", Target=" + sampleRateTarget
+ ", filterSize=" + filterSize + ", numResampleOperations=" + numResampleOperations
+ "} ";
}
public String getCreator() {
return "new NodeResample(" + incrementL + "," + decrementM + "," + sampleRateSource + "," + sampleRateTarget + "," + "0.0" + "," + filterSize + "," + numResampleOperations
+ ")";
}
@Override
public int hashCode() {
int hash = 3;
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final NodeResample other = (NodeResample) obj;
if (this.incrementL != other.incrementL) {
return false;
}
if (this.decrementM != other.decrementM) {
return false;
}
if (this.sampleRateSource != other.sampleRateSource) {
return false;
}
if (this.sampleRateTarget != other.sampleRateTarget) {
return false;
}
if (!Objects.equals(this.filterSize, other.filterSize)) {
return false;
}
return true;
}
}
我想使用Java Streams进行翻译
但是，我感到沮丧...
List<NodeResample> minimumlistPerValueNew = nestedListPerValue.stream()
.min(
Comparator.comparingLong(map(listPerValue -> {
TreeNodeResample temp = new TreeNodeResample(null);
temp.setNestedListsValue(out.getNestedListsValue());
temp.addListValue(listPerValue);
return temp.getListNodes();
})
//.map(node -> node::getValue)
.filter(nodeResample -> nodeResample != null)
.mapToLong(NodeResample::getNumResampleOperations).sum())
)
.orElse(Collections.emptyList());
恢复情况
public CustomObject wrapperMethod(List<CustomObject> listCustomObjects) {
Long lastMinimum = Long.MAX_VALUE;
CustomObject minCustomObject;
for (CustomObject customObject : listCustomObjects) {
Long returnedValue = anyMethodReturningLong(customObject);
if (returnedValue < lastMinimum) {
lastMinimum = returnedValue;
minCustomObject = customObject;
}
}
return minCustomObject;
}
最佳答案
您也可以尝试Stream.reduce()解决您的问题。
我从您的问题中了解到的是，存在一个nestedList，并且要从那些内部列表中返回与您的最低标准匹配的列表。
例如，假设我们有这样的[[1,2,4],[5,6,7,8,9,10],[11,12]]嵌套列表，现在您要返回最小list.size（）的列表。试试下面的代码：
import java.util.*;
import java.util.stream.*;
public class Main
{
public static void main(String[] args) {
List<List<Integer>> nestedList = Arrays.asList(
Arrays.asList(1,2,4),
Arrays.asList(5,6,7,8,9,2,5),
Arrays.asList(10,11,12,13,0));
Optional<List<Integer>> oplist = nestedList.stream()
.reduce((list1, list2) -> list1.size() < list2.size() ? list1 : list2);
oplist.ifPresent(System.out::println);
}
}
输出：[1,2,4]
希望您能从方法中得到启发。现在，您可以尝试在reduce方法中进行比较检查，并检查它是否适合您。
恢复状态的解决方案
//Using .reduce() method
Optional<CustomObject> minCustomObjectList = listCustomObjects.stream()
.reduce((lastMinimum, returnedValue) -> anyMethodReturningLong(returnedValue) < anyMethodReturningLong(lastMinimum) ? returnedValue : lastMinimum);
minCustomObjectList.ifPresent(e -> System.out.println("Minimum Object using reduce method "+e.toString()));
//Using .min() method
CustomObject minCustomObject = listCustomObjects.stream()
.min(Comparator.comparingLong(e -> anyMethodReturningLong(e))).get();
System.out.printf("Minimum Object using min method"+minCustomObject.toString());